What do I see when I turn out the light?

Something I’ve always wondered, and since it’s on the radio right now I might as well ask for some opinion…

What exactly is it that Joe Cocker/The Beatles see “when they turn out the light” that they “can’t tell you but I know it’s mine”?

You see the result of the rods and cones in your retina firing randomly due to sheer boredom. :smiley:

That’s what I always thought, but… me and my dirty mind. :slight_smile:

Here’s a more interesting experiment: Look at a bare light bulb which is off, while finding the switch for the bulb with your hand. Close your eyes without moving your head at all. Wait a few seconds for your eyes to get used to the dark. Turn the light on. Now turn the light off and immediately open your eyes. You should see the filament of the bulb cool down, passing rapidly from white through red to duller red to black. The (typically horseshoe-shaped) outline of the filament should be clear.

You can’t see this ordinarily because the bulb cools off faster than your eyes can adapt to the lower light level. But if you close your eyes while the bulb is on, you can “pre-adapt” your eyes, and see the cooling filament.

If you try this with a fluorescent bulb, however, you won’t see a damn thing, because those bulbs are not incandescent – they turn off essentially instantly.